How to convert salt water to fresh water in your backyard. Seriously.
Though there are many ways to turn saltwater into fresh water, some stand out. The EDDI is a smart desalinator that uses a process called electrodialysis, using electricity to separate the water and the salt.
The machine is intended for small farms and home gardens that need to refresh soil salinity and even works to make fresh drinking water.
Support the creators, they have released their plans to the public.
And here are the plans
We started with a simple CAD drawing
We heard about a method called Electrodialysis, where electrical current is used to separate salt ions from water, and we wanted to try it out.
here's the other side
The Valve Circuit
This is our final iteration (out of like 10) of our valve circuit. The valves we were using are latching bipolar valves, so we needed a way to control polarity, and turn it off in general.
The Valve Circuit
This is our final iteration (out of like 10) of our valve circuit. The valves we were using are latching bipolar valves, so we needed a way to control polarity, and turn it off in general.
Our tester prototype
We wanted to build a test prototype to make sure everything would fit together nicely without leaking. The white frames are HD polyethylene, and the yellow parts are Ion Exchange Membranes.
Tester Assembled
The bolt holes took some convincing, but we finally punched through! This one leaked pretty heavily, so we decided we needed some gaskets for the next one.
Cutting Ion Exchange Membranes
This is a few of us cutting holes into the membranes for the bolts and the water flow. This was tedious work!
One of the electrode sides
We used graphite for our electrodes because it doesn't rust, and it's cheap. The plastic here is Polypropylene. We used marine wire sockets to carry the wire from inside the box to the outside.
We've assembled the minimum 8 layers!
And a pusheen for scale
All layers assembled
Seen here is our final box. It's a short box by most standards, but this is really just a proof of concept.
With plumbing attached
We used check valves for the in-flow, and latching solenoid valves for controlling whether the water is salty and recirculated, or the water is clean and passed through to the outlet.
Now to the circuits
This is the most basic element of our circuit. It turns a 3.3v low current signal into a full 5v USB-current.
The Samsung Artik board
pictured here is some of our circuitry with the Samsung Artik board, which is what we used as the "brain" of our project. It's got plenty of pins and it runs Linux.
Solder Suckers
Sometimes we make mistakes (blown transistors). When they happen, you gotta pull the solder off of them.
A fully soldered unit
We used Perma-Proto Boards from Adafruit. Saved a ton of wires.
Some more of our units
You can see those relays. They are much more durable than transistors.
Planning the alignment
The middle box is our power supply for items that need high current. All the boards on the outside are how we translate a signal from the Artik board to a higher control voltage.
Starting to assemble the circuit
We used some scrap pieces of plastic to assemble the circuits and board in an organized fashion. This is about when we started to realize how crazy this is.
Finding a spot for the circuits
We began to test where the circuits could go in relation to the rest of the box.
Double Decker
We realized all our circuits needed two decks, so we built a double decker circuit. One deck was the lower power circuitry, and the other deck was where all the high power stuff went.
Coming together
Everything started coming together now. The bowing on the top deck was a bit pronounced, so we'll probably fix that soon.
A proper lid
More scrap polypropylene for the lid.
To the roof!
We were building this in a small apartment in Manhattan, so the only place we could test was the roof! Somehow we got this up a ladder. In separate pieces of course.
There's the water!
And the water is coming through. Our salinity sensors weren't too accurate, so the results on this are still to come. If you're into voting, we'd love your vote! Login to devpost and vote here: http://devpost.com/software/eddi-electrodialysis-desalinator-for-irrigation